Friday, 15 March 2013

Pesky Wood Racks Update

Here's an update (Mar 15th 2013) with the new freestanding rack (10' x 6' high x 18" deep) now in place that can take 5500 lbs (2500kg) of evenly distributed weight over its 5 shelves.

Preparing the area

All my lumber, including the straw that broke the camels back, is now on this. I have even been able to leave an 8" gap behind the rack to fit sheet goods in. The utilization of space is now better than before as most of the 10" wide x 4/4 8/4 x 10 foot long boards were always on the floor so didn't contribute to the wall crack. They are now on the bottom shelf of the rack.
I just have a whole bunch of Triton wood racks to do something with now :)

End frames assembled

Rack completed
Stock on board
with all my sheet goods in the gap behind

Thursday, 14 March 2013

Pesky wood racks

OK so as part of my shop rebuild I bought some metal wall racks from Triton. They are superb, strong, well made and fix straight to the wall.

Original Triton Racking

The walls are made from Thermalite SHIELD blocks and line the internal walls. These are a solid but lightweight building block.

Thermalite SHEILD block

The external walls are the existing pre-cast concrete sections. The Thermalite blocks are essentially fixed to the external walls with standard wall ties and there is a small cavity in between inner and outer skins. Are you following me so far?
I got a load of timber boards and stacked them on the wall racks and all was good. Or so I thought....

It turns out that I may have been a little over zealous in stacking some oak at one end. One day last week I noticed a crack in the wall, not immediately next to the racks, that went through the centre of two of the blocks and then following the mortar seam of two other blocks. My first thought was settlement cracks. Then I noticed a bigger crack in the wall immediately next to one of the wall racks. Oh crap!!!
Not as bad as I originally thought

On closer investigation the rack was still securely fixed to the wall, its just the wall had moved, only 2mm (3/32") , in a small area out of plumb. It seems that the weight of the lumber on the rack had caused a turning moment due to the short cantilever of the racks and had pushed the internal wall (locally) outwards at the bottom end of one of the uprights of the rack.

Needless to say I removed all the lumber from the racks and examined the wall. It was still sound fortunately but a little dented.

Today I received some expensive, heavy duty, free-standing metal racking 2.5 metres long by 1.8 metres high. It has 5 shelves and is tonight's building job. (see my next blog update)
The free standing rack that
I should have bought in the first place (DOH!)

So the moral of the tale is make sure your wall is strong enough to withstand the weight of the wood you want to put on it BEFORE you decide to buy some wall mounted lumber racks!

Boy this woodworking hobby is expensive huh?

Tuesday, 5 March 2013

Display Cabinet Part 2

The build of the display cabinet is going really well at the moment.
A template was made with the curve of the front. From this the side panels were cut out and then routed with a pattern following bit.
I have routed the mortises in the top and bottom panels. I also made full length tenons on the side and centre panels.
mortise and tenon detail from
Sketchup model

As the customer has asked for adjustable shelves I made a jig to make the holes in all the side and centre panels. Essentially all this is a piece of 3/4" scrap plywood with a hole pattern drilled in relative to two squared and jointed datum edges.

Drill jig turned on its side
The holes in the drill jig are on 32mm centres and are 35mm in from the long edge. The second set of 3 holes are 50mm further in from the first set. The reason for these is because the lower shelves are deeper than the upper shelves so the supports are on different centres. The shelves will follow the graceful lines of the curve of the front so the support holes are changed accordingly.
Shelf support holes
The jig holes are 5/8" diameter and are used for the router guide bush.
The holes in the side panels and centre panel are 8mm x 8mm deep and are transferred through using the router.
The front of the lower and upper panels were then run through the table saw with the blade set at corresponding angles to follow the curve. I have left about 1/16" to remove with a plane after the glue up.

Glue Up

The final job prior to glue up was to sand all internal surfaces to 220 grit. I wouldn't get much opportunity to do sanding properly if everything was already glued up.

The lower tenons are glued into the base using West Systems epoxy quick set. This has quite low viscosity when it has just been mixed. So for the upper tenons I just used regular yellow glue to avoid any drips from squeeze out eminating from above.
The epoxy takes about 7 hours to setup and 48 hours to reach full cure whereas the yellow glue takes about 24 hours to reach full strength. The rear panels are not glued in just slid into their grooves.

The whole assembly was then clamped making sure that everything was square and put aside for a couple of days. Even after taking care not to put too much epoxy on the joints there is still a little squeeze out that will be removed with a chisel plane.

Front view of clamp-up
The grain runs from left to right
as per the original cabinet

Rear view 
Side view showing graceful curve